WO2000035673A1 - Multilayered film and container - Google Patents

Abstract

A multilayered film comprising five layers in which the first, third, and fifth layers are made of an ethylene/α-olefin copolymer having a density of 0.930 to 0.950 g/cm3 and the second and fourth layers are made of a resin blend comprising 35 to 55 wt.% polypropylene having a density of 0.900 to 0.930 g/cm3, 40 to 60 wt.% ethylene/α-olefin elastomer having a density of 0.860 to 0.900 g/cm3, and 2 to 8 wt.% high-density polyethylene having a density of 0.955 to 0.970 g/cm3; and a container made of the film (bag for fluid transfusion, etc.). The multilayered film and the container are useful in medical applications.

Description

 Specification

 Multilayer film and container

Technical field

 The present invention relates to a multilayer film and a container formed using the same, and more particularly, to a multilayer film and a container used in the medical field, particularly as a material for containing a chemical solution, blood, and the like. Background art

 In order to improve the properties of medical flexible plastic containers such as infusion bags, it has been attempted to employ a multilayer film as a material. Examples of conventional multi-layer medical containers include those made of the following polyethylene resins.

 1) JP-A-62-64363

A three-layer bag made of linear low-density polyethylene, wherein the density of the inner and outer layers is 0.920 g / cm ³ or more, and the density of the middle layer is less than 0.920 g / cm ³ .

 2) Japanese Patent Publication No. 63-248633

Three layers consisting of linear low density polyethylene, density 0.9 10-0 of the inner and outer layers. 940 g / cm \ density of the intermediate layer is 0.880 to 0. In 905 g / cm ^3, both the density of the containers difference is that 0. 0 1 g / cm ³ or more.

 3) JP-A-3-277365

Outer layer density 0. 920 g / cm ³ or more linear low density polyethylene, intermediate layer density 0. 9 1 5 g / cm ³ or less linear low density polyethylene, the inner layer density 0. 9 18 g Three-layer bag made of branched low-density polyethylene of / cm ³ or more.

 4) JP-A-4-26675-9

Inner and outer layers to the density 0. 930 g / cm ³ or less long chain branching low-density polyethylene Density 0 945 g / cm ³ or more high-density polyethylene with 5-40% mixed resin, the intermediate layer density 0. 920 g A bag of three or more layers made of a resin in which 15% or less of the high-density polyethylene is mixed with linear low-density polyethylene of / cm ³ or less.

However, the conventional medical multilayer container has one of the following disadvantages. ing.

 (i) The heat resistance is not sufficient because the inner and outer layers of the film are made of low-density polyethylene resin, and the seal strength and drop strength are reduced by sterilization under high-temperature conditions such as high-pressure steam sterilization and hot water sterilization. descend.

 (ii) Blocking easily occurs after sterilization under the above-mentioned high temperature conditions (low blocking resistance).

 (iii) Since the strength of the film is low, it is necessary to increase the thickness.

 (iv) The bag making speed cannot be increased because the tensile strength of the film is not sufficient.

 (V) Heating cannot be performed in a short time because the temperature of the heater cannot be raised during heat sealing (low sealing performance).

 (vi) The transparency and flexibility of the film are reduced after sterilization.

 When manufacturing a medical container (infusion bag) 10 as shown in FIG. 1, two films 22 are superimposed, and a member (port) 20 is inserted between the two films 22. In this state, the periphery of the film 22 is heat-sealed.

 However, as shown in FIG. 2, since the film 22 bends greatly in the area adjacent to the member 20, when heat sealing is performed using a conventional multilayer film, the film expands at the bend 24 and the film thickness increases. It became thin, and pinholes might be generated.

 Therefore, an object of the present invention is to provide a multilayer film which is excellent in heat resistance, blocking resistance, strength, sealability, transparency and flexibility, and which can prevent generation of pinholes in a bent portion during heat sealing. It is to provide a container. Disclosure of the invention

 The inventors of the present invention have conducted intensive research to solve the above-mentioned problems, and have formed a three-layer structure of the intermediate layer, a resin or mixed resin disposed in each layer, and a layer of the entire multilayer film. As a result of various studies on the combination of configurations, a completely new resin composition that can improve the heat resistance without impairing the basic properties such as transparency and flexibility, and the combination of the arrangement of the resin were found. This led to the completion of the present invention.

That is, the present invention relates to a multilayer film comprising five layers, Layer is the (A) Density 0 · 930~ 0. 950 g / cm 3 of ethylene flying one year old Refuin co polymer, the second layer (B) Density 0. 9 10~0. 930 g / cm 3 Ethylene-Hyperolefin copolymer 30-60% by weight, Density 0.860-0.900 g / cm ³ Ethylene olefin elastomer 35-65% by weight and Density 0.955- 0. 970 g / cm ³ in the mixed resins consisting of high density polyethylene 1-10 wt%, or, (C) density 0. 900~0. 930 g / cm ³ polypropylene 35-5 5 wt%, density 0. A mixed resin consisting of 860-0.900 gZcm ³ of ethylene '' one-year-old refin-based elastomer 40-60% by weight and density 0.955-5.970 g / cm ³ High-density polyethylene 2-8% by weight And the third layer is the above-mentioned (A) the ethylene'polyolefin copolymer, or (D) the polypropylene having a density of 0.900 to 0.930 g / cm ³ 40 to 60% by weight and the density of 0.860 to 0. of 900 g / cm ³ ethylene-Fei one Orefu A mixed resin comprising 40 to 60% by weight of an epoxy-based elastomer, and the fourth layer is the mixed resin of the above (C).

 According to the multilayer film of the present invention described above, it is possible to sufficiently prevent the occurrence of binholes, for example, when manufacturing the medical container (infusion bag) 10 described above. In particular, since the heat welding of the port 20 can be performed at a relatively high temperature, and the film does not extend too much at the bent portion 24, it is possible to reliably prevent the occurrence of a binhole at the bent portion 24. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a front view showing an embodiment of the container of the present invention.

 FIG. 2 is a partial cross-sectional view taken along line AA of FIG.

 Explanation of reference numerals

 10 containers

 20 Best Mode for Carrying Out the Invention

In the multilayer film of the present invention, among the above, it is sufficient that the second layer is the mixed resin of the above (C), and the third layer is the ethylene 'olefin copolymer of the above (A). What This is preferable from the viewpoint of reducing manufacturing costs while maintaining heat resistance.

 In the multilayer film of the present invention, the polypropylene used for the mixed resin (C) or (D) has a melt flow rate (MFR) of 1 to 40 g / l 0 min (230 ° C), A melting point of 140 to 170 ° C. is preferred from the viewpoint of compatibility with other resins.

 The proportion of the thickness of each layer in the multilayer film of the present invention is 5 to 15% for the first layer, 25 to 45% for the second layer, 2 to 15% for the third layer, It is preferable that the fourth layer has a range of 25 to 45% and the fifth layer has a range of 7 to 20% .The first layer has a range of 5 to 10%, the second layer has a range of 30 to 45%, and the third layer has a range of 2 to 10%. %, The fourth layer is 30-45% and the fifth layer? More preferably, it is in the range of 15%.

 The container of the present invention is characterized in that any one of the above-mentioned multilayer films is used, and the first layer of the multilayer film is formed as an outer layer and the fifth layer is formed as an inner layer.

 Since the container of the present invention is formed by using the multilayer film of the present invention, it has high heat resistance, good blocking resistance, strength, sealing property, flexibility and transparency, and sufficient generation of bin holes. Can be prevented.

 Hereinafter, the resin of each layer in the multilayer film and the container of the present invention and the method for producing the multilayer film and the container of the present invention will be described in detail.

 The physical properties specified in the present invention are all based on the rules of the American Society for Testing and Materials (ASTM), and the density is ASTM D1505 and the melt flow rate (MFR) is ASTM D1238. The melting point is measured according to ASTM D2117.

 First, the resin, copolymer and elastomer used in the multilayer film of the present invention will be described.

 [Ethylene-Hiorefin Copolymer and Ethylene-Hiorefin Elastomer]

Examples of olefins in the title copolymer or elastomer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-1-pentene, 1-heptene, 1-octene, 1-octene —Oneolefin having 3 to 12 carbon atoms, such as —nonene, 1-decene, 1-decene, and 1-dodecene. As the title copolymer or elastomer, those having a single branched chain produced by a medium-to-low pressure method are particularly preferably used.

 (High-density polyethylene)

 The high-density polyethylene described above may be a homopolymer of ethylene or a copolymer with ethylene glycol. Examples of the monorefin include the above-mentioned monorefin having 3 to 12 carbon atoms. Although the content ratio of the monoolefin is not particularly limited, it is usually set in the range of 0.1 to 5 mol%.

The high-density polyethylene used in the present invention has a density in the range of 0.955 to 0.970 g / cm ³ , and among them, one having an MFR of 1 to 30 g / 10 minutes (190 ° C) It is suitable. The title polypropylene may be a homopolymer of propylene or a copolymer containing a small amount of ethylene or α-olefin. As the one-year-old refin, for example, the one-year-old fin having the carbon number of about 4 to 12 among the above-mentioned one-year-old fins such as 1-butene is exemplified. In addition, the content ratio of Hiichi Sai Refin is usually set within the range of 10% by weight or less.

The polypropylene used in the present invention has a density in the range of 0.900 to 0.930 g / cm ³ , especially having an MFR of 1 to 40 g / 10 minutes (230 ° C) and a melting point of 140 to Isotactic polypropylene in the range of 170 ° C is preferably used.

 Next, the mixed resin constituting the multilayer film of the present invention will be described.

[Density 0.9 10-0. Ethylene 930 g / cm ^3. Fei one Orefin copolymer 30-60 wt%, a density from 0.860 to 0. Of 900 g / cm ³ Ethylene 'shed Ore Fi down elastomers ethylene, which constitutes one 35-65 wt% and density 0. 955~0. 970 g / cm ³ density polyethylene 1-10 wt% of a mixed resin (mixed resin (B))] the title mixed resin (B) · As the polyolefin copolymer, ethylene ′, a polyolefin elastomer and a high-density polyethylene, those having a density within the specified range among the above-mentioned examples are used.

The density of the ethylene-olefin copolymer is particularly high in the marked range. W

Preferably a 0. 9 1 5~0. 925 g / cm 3 in. The MFR is preferably from 1.0 to 5.0 g / 10 min (190 ° C), and the melting point is preferably from 115 to 25 ° C.

It is preferable that the density of the ethylene-one-year-old olefin-based elastomer is particularly in the range of 0.870 to 0.890 g / cm ³ in the range of the title. Further, the MFR is preferably 0.1 to 2.0 g / 10 minutes (190 ° C).

 The high-density polyethylene preferably has an MFR of 1 to 30 g / 10 minutes (190 ° C.).

 The mixing ratio of the ethylene-polyolefin copolymer, the ethylene-polyolefin copolymer and the high-density polyethylene constituting the mixed resin (B) in the order of 35 to 55 in the range of the title %, 40 to 60% and 3 to 8% by weight.

 If the proportion of each resin constituting the mixed resin (B) is out of the above range, problems such as a decrease in flexibility and heat resistance, a decrease in moldability, and a decrease in pinhole resistance are caused. Occurs.

[Density 0. 900~0. 930 g / cm Polypropylene 35 ³ to 55 wt%, density 0. 860~0. 900 g / cm ³ of ethylene 'shed one Orefi emissions based elastomers 40-60 wt% and density 0. 9 55 ~ 0. 970 g / cm 3 of density polyethylene having 2 to a mixed resin consisting of 8 wt% (mixed resin (C))]

 Examples of the polypropylene, ethylene-one-year-old olefin-based elastomer, and high-density polyethylene which constitute the title mixed resin (C) include those having a density within the title range among the above examples.

 Among the polypropylenes whose density is in the specified range, isopropanol having an MFR of 1 to 40 g / 10 min (230 ° C) and a melting point of 140 to 170 ° C is used, as described above. It is preferably polypropylene.

 The preferred range of the density, MFR or melting point of the ethylene-olefin-based elastomer and the high-density polyethylene is the same as described above.

The mixing ratio of the polypropylene, ethylene-one-year-old olefin-based elastomer and high-density polyethylene that make up the mixed resin (C) is 4 It is preferably 0-50% by weight, 45-55% by weight and 3-7% by weight. If the ratio of each resin constituting the above-mentioned mixed resin (C) is out of the above range, problems such as a decrease in flexibility and heat resistance, a decrease in moldability, and a decrease in pinhole resistance are caused. Occurs.

 In particular, if the mixing ratio of the high-density polyethylene exceeds the above range, molding becomes difficult and a film cannot be obtained. Conversely, when the ratio is below the above range, appearance problems such as a large number of wrinkles are generated when the container is formed using the multilayer film.

[Density from 0. 900~0. 930 g / cm Polypropylene 40-60 of ³ wt% Contact and density 0. 860 ~ 0. 900 g / cm 3 of ethylene 'shed one Orefin system Elastica Tomah one 40-60 wt% Mixed resin (Mixed resin (D))

 As the polypropylene and the ethylene / ethyl olefin elastomer which constitute the title mixed resin (D), those having the density within the title range among the above-mentioned examples are used.

 The preferred range of the density, MFR or melting point of the polypropylene and the ethylene 'phosphorefin-based elastomer is the same as described above.

 It is preferable that the mixing ratio of the polypropylene and the ethylene-based olefin-based elastomer constituting the mixed resin (D) is 40 to 50% by weight and 50 to 60% by weight, respectively, in the range of the title.

 If the ratio of each resin constituting the mixed resin (D) is out of the above range, problems such as a decrease in strength and a decrease in binhole resistance occur.

 Next, each layer of the multilayer film of the present invention will be described.

 (First and fifth layers)

 The first layer and the fifth layer in the multilayer film of the present invention are the layers that become the outer layer and the inner layer of the medical container, respectively. The first layer (the outer layer) has mechanical strength (particularly, tensile strength) and heat resistance. The fifth layer (inner layer) is required to have sealing properties and blocking resistance.

For the first layer and the fifth layer, as a resin having the above properties, an ethylene / polyolefin copolymer having a density of 0.930 to 0.950 g / cm ³ is used. Among the copolymers, in particular density 0.9 35-0. 945 / Rei_111 ^3, 1? Those having an R of 1.0 to 5.0 g / 10 minutes (190 ° C) and a melting point in the range of 120 to 130 ° C are more excellent in the above properties and are more suitable. Used for The ratio of the thickness of the first layer (outer layer) is preferably 5 to 15%, more preferably 5 to 10%, based on the thickness of the entire film. If the ratio of the thickness of the first layer is below the above range, the mechanical strength and heat resistance of the multilayer film or the medical container may be insufficient. Conversely, even if the thickness exceeds the above range, there is no significant change in mechanical strength or heat resistance, and the flexibility of the multilayer film may be reduced.

 On the other hand, the ratio of the thickness of the fifth layer (inner layer) is preferably from 7 to 20%, more preferably from 7 to 15%, based on the thickness of the entire film. If the ratio of the thickness of the fifth layer is below the above range, the sealing property of the multilayer film may be reduced, and the appearance of the container may be deteriorated. Conversely, even if the thickness exceeds the above range, there is no significant change in the sealing property and the blocking resistance, and the flexibility of the multilayer film may be reduced.

 (2nd layer)

 The second layer in the multilayer film of the present invention is one of three intermediate layers, and the mixed resin (B) or (C) is used to provide flexibility without impairing the heat resistance of the multilayer film. ) Is used.

 The ratio of the thickness of the second layer is preferably 25 to 45%, more preferably 30 to 45%, based on the thickness of the entire film. If the thickness ratio is out of the above range, the flexibility of the multilayer film and the container may be insufficient, or the heat resistance / pinhole resistance may decrease.

 (3rd layer)

 The third layer in the multilayer film of the present invention is the most intermediate layer in the three-layer intermediate layer, and the ethylene used for the first layer and the fifth layer in order to maintain the strength of the multilayer film. · Α-refined copolymer (Α) or mixed resin (D) is used.

The ratio of the thickness of the third layer is preferably 2 to 15% based on the thickness of the entire film. If the thickness ratio is out of the above range, the strength of the multilayer film and the container will be insufficient. W

It may be insufficient or the flexibility may be impaired even if the strength is maintained.

 (4th layer)

 The fourth layer in the multilayer film of the present invention is one of three intermediate layers, and the mixed resin is used to impart heat resistance while maintaining the flexibility of the multilayer film.

 The ratio of the thickness of the fourth layer is preferably from 25 to 45%, more preferably from 30 to 45%, based on the thickness of the entire film. The problem when the thickness ratio is out of the above range is the same as in the case of the second layer described above.

 According to the multilayer film of the present invention, by setting the layer structure, especially the structure of the intermediate layer (second to fourth layers) as described above, the flexibility (elasticity) of the entire film is maintained while the entire film is maintained. It is possible to maintain the strength of the steel, and to further improve the heat resistance.

 Therefore, it is possible to provide a safe container that can sufficiently withstand a pinhole test and a drop test under severe conditions.

 Next, a method for producing the multilayer film of the present invention will be described.

 In order to produce the multilayer film of the present invention, a water-cooled or air-cooled coextrusion inflation method, a coextrusion T-die method, a dry lamination method, an extruded lamination method, and the like can be used. It is preferable to use the water-cooled co-extrusion inflation method and co-extrusion T-die method in terms of transparency, economy and hygiene.

 In either method, it is necessary to carry out the process at a temperature at which the resin in each layer melts. However, if the temperature is excessively increased, a part of the resin undergoes thermal deterioration, and the performance may deteriorate due to the degraded material. Therefore, the temperature condition for producing the multilayer film of the present invention is usually from 150 to 250 ° C, preferably from 170 to 200 ° C.

 The thickness of the film of the present invention produced as described above is generally 100 to 350 ^ m, preferably 200 to 300 m, but can be appropriately increased or decreased depending on the purpose of use and the like. Sufficient strength is maintained even with a thickness of about 250 m.

Next, the container of the present invention will be described with reference to FIG. 1 showing one embodiment thereof. You.

 FIG. 1 is a front view showing an example of a medical container (infusion bag).

 The medical container 10 is obtained by cutting the two sheet-like multilayer films obtained as described above by an ordinary method, superimposing the respective fifth layers as inner layers, heat sealing the periphery of the container 10, and furthermore, The container 10 having a predetermined shape and dimensions is manufactured by attaching the container 10 by means such as heat sealing. Alternatively, the container 10 may be formed by heat sealing after being formed into a tube with the fifth layer of the multilayer film inside. Here, as a condition for heat sealing the film, a temperature range of 130 to 200 ° C. can be adopted. For example, in the case of a film having a thickness of about 250 It can be sealed in a short time of 0.5 to 6 seconds.

 It is preferable to use, as the member 20, a resin which is excellent in adhesion to the fifth layer in the multilayer film of the present invention, for example, a resin molded with polyethylene. (B) When the member 20 is made of polyethylene having a melting point of about 120 to 130 ° C, the heat sealing conditions are as follows. Heat for 5 to 5 seconds. Example

 Hereinafter, the multilayer film and the container of the present invention will be described with reference to Examples, Comparative Examples, and Test Examples.

 The components constituting the mixed resin used in the examples and comparative examples are as follows. [Ethylene / Hiolefin Copolymer]

 (1) Ethylene 1-butene copolymer [Mitsui Chemicals Co., Ltd., density = 0.920 g / cm MFR = 2.1 g / 10 minutes (190 ° C)]

 (Ethylene / Hyorefin-based elastomer)

(2) Ethylene '1-butene copolymer elastomer [Mitsui Chemicals Co., Ltd., density = 0.885 g / cm ³ , MFR = 0.5 / 10 minutes (190 ° 0]

 (High-density polyethylene)

(3) Ethylene 1-butene copolymer [Mitsui Chemicals, Inc., density = 0.962 g / cm ³ , MFR = 15 g / 10 min (1 90 ° C)]

 (Polypropylene)

(4) Isotactic polypropylene (ethylene content: 5% by weight or less) [manufactured by Mitsui Chemicals, Inc., density: 2,910 g / cm ³ , MFR = 1.6 / 10 minutes (230 ° C)] The resins shown in Table 1 are as follows.

 (Ethylene / hydrophorin copolymer of the above (A))

A-1: Ethylene / 1-butene copolymer [Mitsui Chemicals Co., Ltd., density = 0.940 g / cm ³ , MFR = 2.1 g / 10 min (190 ° C)]

 (The mixed resin of the above (B))

B-1: A mixed resin composed of 45% by weight of the copolymer of (1), 50% by weight of the elastomer of (2), and 5% by weight of high-density polyethylene of (3) (density of mixed resin = 0.96 g / cm ³ )

 (The mixed resin of the above (C))

 C-1: Mixed resin consisting of 45% by weight of polypropylene of (4), 50% by weight of elastomer of (2) and 5% by weight of high-density polyethylene of (3)

 C-2: A mixed resin consisting of 41.5% by weight of the polypropylene of (4), 53.5% by weight of the elastomer of (2) and 5% by weight of the high-density polyethylene of (3).

C-3: A mixed resin comprising 30% by weight of the polypropylene of (4), 65% by weight of the elastomer of (2) and 5% by weight of the high-density polyethylene of (3).

 C-4: Mixed resin consisting of 45% by weight of polypropylene of (4), 45% by weight of elastomer of (2) and 10% by weight of high-density polyethylene of (3)

 (Mixed resin of (D))

 D-1: Mixed resin consisting of 45% by weight of polypropylene of (4) and 55% by weight of elastomer of (2)

 Examples 1 to 5, Comparative Examples 1 to 4

 (Manufacture of multilayer film)

Using the above resins A-1, B-1, C-1 to C-4 and D-1 (mixed resin), films with the layer composition shown in Table 1 below were formed by water-cooled coextrusion inflation. . The multilayer film of Comparative Example 2 was a four-layer film having no layer corresponding to the third layer. W

 12

Was

 In Comparative Example 4 in which the composition of the mixed resin (C) used in the second and fourth layers as the intermediate layers was out of the range of the present invention, molding was difficult and a film could not be obtained. Was.

 [table 1]

 Above ■ HE i villages

H 3 ® 4th layer 5th layer

 A-1 B-l A-1 C-l A-1 Example 1 20 πι 100 m 10 / m 100 m 30 m

 A-1 C-l A-1 C-l A-1 Example 2 20 ^ m 100 Aim 10 / m lOO ^ m 30 Am

 A-1 B-l D-l C-l A-1 Example 3 20 πι 95 m 20 m 95 m 30 Mm

 A-1 C-2 A-1 C-2 A-1 Example 4 20 m 100 Am ΙΟ ιη 100 m 30 ιη

 A-1 C-l D-l C-l A-1 Example 5 20 m 95 ιη 20 Mm 95 μm 30 im

 A-1 D-l A-1 D-l A-1 Comparative Example 1 20 πι 100 m 10 / m 100 μm 30 ιη

 A-1 B-l C-l A-1 Comparative Example 2 30 im 100 Mm 100 ηι 30 ηι

A-1 C-3 A-1 C-3 A-1 Comparative example 3 20 m 100 μιη 10 m 100 ιη 30 π

 A-1 C-4 D-l C-4 A-1 Comparative Example 4 20 ιη 95μιη 20 Aim 95 μm 30 Mm

(Manufacture of containers)

 Next, using the films of Examples 1 to 5 and Comparative Examples 1 to 4, a medical container (infusion bag) 10 having a content of 50 Oml as shown in FIG. 1 was produced. When molding the medical container 10, heat sealing of the peripheral portion was performed at 155 ° C for 4.5 seconds, and sealing of the mouth member 20 was performed at 140 to 150 ° C for 3 seconds.

 (performance test)

 Test example 1

With respect to the medical container (infusion bag) 10 obtained using the multilayer films of Examples 1 to 5, evaluation tests of various characteristics were performed by the following methods. • Heat resistance: The container was filled with distilled water and subjected to high-pressure steam sterilization at 110 ° C for 40 minutes, and the container was visually inspected for deformation, bag breakage, and seal leakage.

 • Drop test: After refrigerated at about 4 ° C, the containers were dropped five times each from three directions from a height of 1 m, and the state of bag breakage and seal leakage was visually observed.

 • Flexibility: Spontaneous discharge of the internal solution was visually observed.

 • Transparency: A container was filled with distilled water, subjected to high-pressure steam sterilization in the same manner as described above, visually observed, and further measured at a light transmittance of 45 Onm.

 'Appearance: Observed visually to check for wrinkles, blocking, deformation and breakage. In the above heat resistance, drop test, flexibility, transparency and appearance evaluation, ◎ indicates very good, 〇 indicates good (suitable for practical use), Δ indicates slightly poor (practically inappropriate), and X indicates bad. Show.

 Table 2 shows the test results.

[Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Heat resistance ◎ ◎ ◎ ◎ ◎

 Drop test ◎ ◎ ◎ ◎ ◎

 Flexible ◎ ◎ ◎ ◎

 transparency

 Visual ◎ ◎ ◎ ◎ ◎

 Transmittance% 83.2 83.4 85.3 85.7 88.0 Appearance ◎ ◎ ◎ ◎ ◎

As is clear from the results in Table 2, the container of the present invention obtained very good results in all of the items of heat resistance, drop test, flexibility, transparency and appearance.

 Test example 2

A medical container (infusion bag) 10 obtained using the multilayer films of Examples 1 to 5 and Comparative Examples 1 to 3 was filled with a physiological saline solution, sealed with a rubber stopper, and kept at 110 ° C. The autoclave was subjected to high-pressure steam sterilization for 40 minutes. After processing, use a simple capacitance type binhole test Yuichi [Dinseisei Co., Ltd. binhole test Yuichi H type] to obtain a pinhole. Nothing was inspected.

 Inspection was conducted on containers that were sealed under the three conditions of 140 ° (, 150 ° C and 150 ° C), respectively. ^ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ Undere _ _ Therefore, if the ratio of samples in which binholes occurred was less than 5% (less than 5 out of 90 samples) under these conditions, it was determined that the binhole resistance was good. Shows the number of samples in which binholes were detected and the ratio (.).

[Table 3] Example Comparative example

 1 2 3 4 5 1 2 3 Number of specimens 4 1 3 4 0 9 15 Ratio (%) 4.4 1.1 4.4 3.3 4.4 0 10.0 16.7 As is clear from Table 3, the containers of Examples 1 to 5 were all pinholes. The proportion of specimens in which pitting occurred was less than 5%, and the binhole resistance was good.

 On the other hand, the composition of Comparative Example 2 which is a four-layer multilayer film and the mixed resin (C) used for the second and fourth layers which are the intermediate layers are out of the scope of the present invention. Compared with Comparative Example 3, the proportion of specimens with pinholes was large, and the binhole resistance was not practically sufficient.

 In Comparative Example 1 in which the mixed resin used in the second and fourth layers, which are the intermediate layers, did not contain high-density polyethylene, the proportion of specimens with pinholes was 0%, The hole property was extremely excellent. However, the appearance was extremely inadequate, with many wrinkles observed after sterilization, making it unsuitable as a medical container.

In the present invention, a film having a layer structure shown in Table 4 below can be formed in the same manner as in Examples 1 to 5. These films also have the same excellent properties as described above. [Table 4] Upper: resin type, lower: thickness

 1 eyebrows Brother <3rd layer 4th layer 5th calendar

11 A-l- 2 A-l Example 6 20μπι 100 ιη 10 im 100 μπι 30 m

 A-l B-l D-l C-2 A-l Example 7 20 μπι 100 μιη 10 m 100 μιη 30Atm

 A-l C-l A-l C-2 A-l Example 8 20 ηι 100 μπι ΙΟμπι 100 μπι 30 Mm

 A-l C-l D-l C-2 A-l Example 9

 Example 10 20 μιη 100 πι 10 μιη 100 πι 30um

 A-l C-2 D-l C-l A-l Example 11 20 ηι 100 Mm ΙΟμηι 100 Mm 30 im

 A-l C-2 D-l C-2 A-l Example 12 20 πι 100 πι ΙΟ ιη 100 im 30 m

INDUSTRIAL APPLICABILITY The multilayer film and the container according to the present invention are excellent in heat resistance, blocking resistance, strength, sealability, transparency, flexibility and appearance, and furthermore have a binhole at a bent portion or the like during heat sealing. It has the advantage that no blood is generated, and can be suitably used as medical containers such as infusion bags and blood bags.

Claims

The scope of the claims 1. a multilayer film consisting of five layers, The first layer and the fifth layer are (A) an ethylene′-one-strength olefin copolymer having a density of 0.930 to 0.950 g / cm ³ ,  5 The second layer (B) Density 0. 9 10~0. 930 g / cm 3 of ethylene 'shed one Orefin copolymer 30-60 wt%, a density from 0.860 to 0. Of 900 g / cm ³ ethylene · alpha-O les fin elastomers one 35-65 wt% and density 0. 955~0. 970 g / cm ³ density polyethylene 1 mixed resin consisting of 10 wt% or, 10 (C) Density 0.95 to 0.930 g / cm ³ polypropylene 35 to 55% by weight, Density 0.860 to 0.900 g / cm ³ ethylene / α-olefin elastomer 40 to 60% by weight and density from 0.955 to 0. a 970 mixed resin consisting of high density polyethylene having 2-8 wt% of g / cm ^3,  The third tier  15 The ethylene'-one-year-old olefin copolymer of the above (A), or (D) Density 0. from 900 to 0. 930 g / cm ³ Polypropylene 40-60% by weight per cent and a density from 0.860 to 0.900 ethylene flying one Orefin system Elastica Tomah one 40-60 weight g / cm ³ % Mixed resin, and  The fourth layer is the mixed resin of the above (C)  20. A multilayer film, which is 20. 2. The multilayer film according to claim 1, wherein the second layer is the mixed resin of (C), and the third layer is the ethylene′-one-strand olefin copolymer of (A). E5 3. The polypropylene according to claim 1 or 2, wherein the polypropylene is an isotactic polypropylene having a melt flow rate (MFR) of 1 to 40 g / 10 minutes (230 ° C) and a melting point of 140 to 170 ° C. Multilayer film. 4. The ratio of the thickness of each layer is First tier: 5-15%, Tier 2: 25-45%, Third tier: 2-15%, Fourth layer: 25-45%, Fifth layer: 7-20% The multilayer film according to any one of claims 1 to 3, wherein 5. The ratio of the thickness of each layer is First layer: 5 ~: L 0%, Second layer: 30-45%, Third layer: 2-10%, Tier 4: 30-45%, Fifth layer: 7 ~: L 5% 5. The multilayer film according to claim 4, wherein 6. The multilayer film according to claim 4, wherein the thickness of the entire film is 200 to 300 / m. 7. A container formed by using the multilayer film according to any one of claims 1 to 6, wherein the first layer of the multilayer film is an outer layer and the fifth layer is an inner layer. 8. The container according to claim 7, wherein a polyethylene mouth member is welded sandwiched between the films.